Railway traffic control apparatus



Sept. 1, 1959 R. L. oswALD ETAL 2,902,594

RAILWAY TRAFFIC CONTROL APPARATUS v d 1 mi @Ns mma M t 0 e WW Wma T @T m wwwmw* m W w W A .wi mj: l 5 4 R @E 2 Si 1H .n mw t 11 Rww mM/W TBL www MESH. ee RLRR y @SNN D von NN NSM. mllllllll- Filed Nov. 23, 1956 Sept. l, 1959 R, OSWALD ETAL 2,902,594

RAILWAY TRAFFIC CONTROL APPARATUS 2 Sheets-Sheet 2 Filed Nov. 25, 1956 THEIR TWOH/VEY United States Patent O i 2,902,594 RAILWAY TRAFFIC CONTROL APPARATUS Robert L. Oswald, Wilkinshurg, and Merrill E. Cornell,

Irwin, Pa., assignors to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application November 23, 19516, Serial No. 623,907 7 Claims. (Cl. 246-219) Our invention relates to railway traffic control apparatus. More particularly our invention relates to control apparatus for a crossover interlocking which permits through train movements` by signal indication on one main track while the other main track is being used for switching moves.

In some remotely operated traffic control systems, generally termed Centralized Traffic Control, two parallel main tracks are signaled for train movements in either direction on each track. In such installations, crossover tracks between the two main tracks are remotely controlled to provide for diverging moves from one track to the other as well as for through train moves on either main track. At such locations it is sometimes necessary to make switching moves in which a local train must occupy one ofthe main tracks. It is very desirable at such times, in order to free the remote control operator of unnecessary work, to permit the switching moves to be made withoutregard to signal indications. These operations generally occur in the vicinity of a `railroad yard or a highly industrialized section. The switching or drilling moves, as they are sometimes termed, are similar in. effect to through train movements along one of the main tracks.

over one switch of the crossover. When permission is given to make such moves without regard to the signal indication, the switch controls must be locked out, that is,` must be removed from the remote` operators control. Such switches therefore must be provided with dual control mechanisms which permit a choice between power operation by the remote operator and manual or hand operation by a local switching crew. The, selection is made by dual selector levers provided as part of the switch mechanisms.

Generally, at such installations under present systems, with one. switch of the crossover in manual operation or in the hand throw position, all the signals at the crossover on both main tracks are held in the stop position. This` is an extreme disadvantage since although only one main track is occupied by the local train, the other track is useless since the signals cannot be cleared for any through train movements. Such a disadvantage defeats one principal purpose of such C.T.C. installations, which is to expedite train movements by taking everyopportunity to advance trains when conditions will permit. Thus it would be highly advantageous if through train movements by signal indication can be made upon the second main track, that` is, the one not being used for switching moves, provided that suchy moves are made under full safety conditions. Such safety measures require that the switch points which are in manual operation must` be locked in their normal position, that is, the. hand throw lever must be fully engaged. Likewise, assurance must be given that these switch points cannot be moved by the operation of the hand throw lever. As a still further safety factor, the arrangement must prevent the clearing of a signal on the second main track which would pennit a diverging move over the crossover onto the switch which is in hand throw operation and over which the train performing the switching moves may be moving.

2,902,594 Patented Sept. 1, 1959 ICC location "while the second or parallel main track is being` used for switching moves.

Another object of our invention is to provide traflc control apparatus by which a through train movement may be authorized by signal indication over one switch of a crossover while the other switch of that crossover is in manual control.

lt is also an object of our invention to provide traffic control apparatus which will permit through train movements, by signal indication and with complete satety protection, along one main track over one switch of a remotely controlled crossover while a parallel main track is being used for switching movements with the second crossover switch in manual operation.

Still a further object ot' our invention is to provide traflic control apparatus by which signals for train moves over one crossover switch are controlled normally by a remote operator while the other switch is in hand throw condition.

Still another object of our invention is trahie control apparatus which assures that a preselected sequence of operations is followed in placing one switch of a crossover in manual operation before the signals which authorize train movement over the other crossover switch maybe cleared by remote control.

A further object of our invention is traflic control apparatus which will assure that the control mechanism for one switch of a crossover arrangement is in a preselected condition of manual control before through train movements along the other main track over the second switch of the crossover may be authorized by a remote control system.

Other objects and features of our invention will become apparent from the drawings as the specification progresses.

ln practicing our invention `we provide, in addition to the usual apparatus, three special purpose relays and an electric switch lock for each switch of a crossover between two main tracks, with each switch being equipped with a dual selector type of switch operating mechanism.

The first of these special relays directly repeats the switchV points in their reverse position with no other check being incorporated in the energizing circuit for this relay. The second of the additional relays repeats the dual` selector lever of the switch mechanism in its normal or power operation position. The third relay stores the reverse switch indication under manual operation, that is, While the selector lever remains in the hand throw position. Finally, the electric switch lock provided for each switch mechanism locks the hand throw lever in the switch normal position.

In the circuit arrangement of our invention, operation of either` dual selector lever to the manual position causes the release of the track indication storage relays for the detector track sections, these relays being usually provided in such remote control systems. However, contacts of the reverse switch storage relay are used to bypass the contacts of the selector repeater relay in the circuit for the track indication storage relay for the opposite detector section, so that this relay is again energized and picks up. Then the normal switch correspondence relay, there being only one of these relays for the two crossover, that is, the switch not being used for the switching operation.

We shall now describe one form of traffic control apparatus embodying our invention and then point out the novel features thereof in the appended claims.

Referring now to the drawings, Figs. 1a and lb, when taken together with Fig. 1a at the top, show diagrammatically one form of trafc control apparatus embodying our invention.

It' is to be pointed out at this time that a suitable source of control current is provided for the apparatus shown in the drawings; This power source preferably is a battery of proper voltage and capacity, but for Vthe sake of simplicity is not shown in the drawings, the'positive and negative terminals thereof being identiiied by the conventional reference characters B and N, respectively. To further simplify the drawings, the operating windings of some of the relays and of the switch locks are shown twice, although the relay control circuits are shown only once. 'This double showing of the control windings establishes the identity of certain scattered relay contacts and other devices which, if relocated nearer to the original showing of the corresponding control winding, would further complicate the drawings. In each case, the second showing of the winding, that is, without the control circuits, is by conventional dotted lines. Certain other conventional illustrations are also utilized in simplifying the drawings, as will be described hereinafter as the speciication progresses.

Referring once again to the drawings, there is shown at the'top of Fig. la a railway interlocking comprising a single crossover track between two'parallel main tracks. Each of these tracks is illustrated by a conventional single line representation. locking is set apart by insulated joints, al-so shown conventionally, into detector track sections. In other words, the rst, or upper main track, as shown in the drawing, includes within the interlocking the detector track section 1T. Similarly, the lower or second main track within the interlocking comprises the detector track section 3T. The crossover track is connected by the switches WA and WB to the first and to the second main tracks, respectively. This crossover track is divided at approximately the center by insulated joints, with the upper half and switch WA being included in detector section 1T and the other half and switch WB being included in detector section 3T.

`Wayside signals are provided to control train movements in veither direction on each of the main tracks and the diverging moves through the crossover from one track to the other. These signals are shown by conventional symbols and are designated as signals 2R and 4R, governing trains moving to the right, and signals 2L and 4L, governing trains moving to the left. Signals 2R and 4L also control train movements through the crossover between the tracks. Any type of wayside signal may be used for this purpose. Thus the complete details of the Each main track within the interspeciiic controls for each of these signals are not shown,

since the different types of controls necessary for the different types of signals are all well known and for simplicity may be omitted from this showing. VSuch portions of the signal control circuits as are shown at the bottom of Fig. 1b to provide an understanding of our invention will be utilized whatever the type of wayside signal used.

Each of the detector track sections is provided with a y track circuit which may be of any usual and well known identical with that just described for switch WA.

, 4 track relay is energzed. When a train occupies any portion of the corresponding track section, the associated track relay is shunted from-fits source of energy and releases.

The interlocking shown in Fig. la is intended to be controlled from a remote location. In other words, this interlocking is merely one ield location in a centralized traic control system which is controlled from one oice location situated at a remote point. Any well known type of remote control system may be used for this control. For example, the remote control system may be similar to that shown in Letters Patent of the United States No. 2,411,375, granted November 19, 1946, to A. P. Jackel for a Remote Control System. For purposes of the succeeding explanation, it is assumed that this system is used here. However, since the details of the remote control form no part of our invention, none of the circuit details are shown in the drawings. It is to be noted, however, that for normal operation of this interlocking, the switches and signals are thus controlled from the remote olice by whatever remote control system is provided.

Each of the switches for the crossover is equipped with a dual selector type operating mechanism. For example, the mechanism for switch WA includes a dual selector lever SA having two positions. The right-hand or normal position, in which it is shownv in the drawing, selects power operation of the switch, while the left-hand position selects manual operation of the switch. Lever SA is operatively connected to a linkY I A, as indicated by the conventional dotted line 5. Thus link IA also has two positions, the right-hand or power operation position and the left-hand or hand operation position; When the link and lever occupy the power operation position, the switch points are controlled by the power operated switch movement SMA, which is indicated diagrammatically in the drawing. The power switch movement SMA Will be more fully explained shortly.

When lever SA and associated link JA occupy the manual operation position, the switch points are connected to the manual or hand throw lever HA. Hand throw lever HA also has two positions. In the righthand or normal position in which it is shown, the switch points are controlled to their normal position, that is, for train movements straight through on the main track. When lever HA is moved to its left-hand or reverse position, the switch points are moved to their reverse position in which trains are diverted from the main track onto the crossover. In other words, as lever HA occupies its normal or reverse position, the switch points are likewise controlled to their normal or reverse position, respectively. The dual selector lever SA is also operatively connected, as conventionally shown by dotted line 6, to a contact member 7 which is likewise operated to its righthand or left-hand, position in correspondence with the operation of the selector lever.

The other switch WB of theY crossover is similarly equipped with a dual selector type operating mechanism In other words, the dual selector lever SB, operatively connected as indicated by a dotted line 8 with the link I B, determines` switch WB will be power operated by power switch movement SMB or will be manually operated by hand throw lever HB. Dual selector lever SB is likewise connected, as shown conventionally by dotted line 9, with contact member 10 which occupies the right-hand (power operation) position or the left-hand (manual operation) position in accordance with the movement of lever SB between its two corresponding positions.

The power operation `switch movements SMA and SMB may be of any suitable type such as, for example, electric or electropneumatic switch machines. These switch machines are controlled in accordance with the usual practico by switch control means comprising the polar relays AW and BW, respectively (Fig. 1b). The exact details of the control circuits are not shown in the drawings, since they form no` .part of our invention. It is believed suicient to state that when either of the polar relays is energized by current of relative normal polarity, it closes its front contacts and operates the polar armature to the normal or left-hand position as viewed in the drawings. The corresponding switch movement SM is then caused to operate the associated switch to the normal position. When the polar ,relays` are energized by current of the opposite or relative reverse polarity to close front ontacts and operate polar armatures to reverse `or right-hand positions, the switch movements are then caused to operate their associated switches to the reverse positions. For example, when relay AW is energized by normal polarity, as is` the condition shown in Fig. lib, power switch movement SMA is energized over front contact 11 and normal contact 1,2 of this` relay and operates to move switch WA to its normal position. lf relay AW is energized by current of the opposite polarity, switch movement SMA is then energized over front contact 11 and reverse contact 12 of relay AW, and operates the switch points of switch WA to their reverse position. Similarly, switch movement SMB is controlled over front contact 13 and normal or reverse contact 14l of relay BW to cause similar operation of switch WB.

Relays AW and BW are controlled `by the switch stick relay WS, which is associated with the remote control apparatus at this iield station. Relay WS is of the magnetic stick type having two windings. This type of relay when deenergized` retains its armature in the last operated position. As shown in the drawing, one of the two windings when energized is capable of positioning the armature to the left-hand or normal position, while the other` winding isv capable of positioning the armature to the right-hand or reverse position. Relay WS is controlled `from the remote control apparatus in the manner selected by the operator at the remote control oice. The details of this operation are not here shown as they are not part of our invention and are identical with the control of the similar relay shown in the `previously mentioned Jackel Patent 2,411,375, reference being made to` this patent Afor complete understanding of the control of relay WS.

The lock relay LR, also shown in Fig. 1b, is used for the purpose of preventing the operation of the switch control relays when local conditions are such that safety considerations require the switches toV be locked in their existing positions. In other words, lock relay LR is released when either track section 1T or 3T is occupied or when any approach control relay AS, to be discussed hereinafter, is` released. When relay LR is released, the opening of its front contact 15 interrupts the connection tfrorn relay WS to the negative terminal of the local power source, so that the control of this relay by the remote control apparatus is ineffective. Similarly, the opening of front. contacts 16, 17, 18, and 19 of relay LR interrupts the control circuits for switch control relays AW and` BW, so that these relays are released, interrupting the control circuits for. the power switch movements SM. When relay LR is energized to indicate that local conditions are safe forv the operation of switches WA andWB, the control circuits for relays AW and BW are completed over front contacts of relay LR and the pole-changing contacts 20 and 21 of relay WS, the operation of` these circuits being obvious from an inspection of the drawings.

`Our invention. adds an electric switch lock to the hand throw leverof each switchmechanism to lock this lever in its normal position. For example, lever HA is operatively connected, as indicated in a conventional manner by dotted line 22, with a locking bar 23 of the electric switch lock AWL. Locking bar 23 is locked or held in the position shown by a segment on armature 24 of switch lock AWL. It is to be noted that these parts of the apparatus are shown conventionally in Fig. la by dotted lines, the complete control for switchslock AWL appearing else- 6 where. It is to be understood` that, as operatively connected by line 22, lever HA in moving from its normal to its reverse position causes locking bar ,2 3 to move from right to left as shown in the drawing. This movement, of course, is prevented Vby the segment `on armature 2,4 when the electric switch lock is deenergized. When switch lock AWL is energized and armature 24 is raised to its upper position, locking bar 23 is free to be moved to the left. Lever HA, being operatively connected to the locking bar, is` then likewise free to move from its normal to its reverse position.

The control circuit for switch lock AWL is shown in Fig. 1b. It is generally the custom to have some type of an initiating contact which performs the final action, if the circuit is otherwise complete, to c lose the energizing circuit for the electric switch look. This contact may be controlled by a padlock which is removed by a trainman, by the opening of the door of a case containing an operating handle for the switch lock, or by the operation of a push button or other `similar means. the control circuit is shown as being completed by a contact which closes upon the removal of a padlock from the electric switch lock mechanism, although any other suitable means may be used. The padlock APL asso.- ciated with switch lock AWL is shown in Fig. lb as controlling three contacts. The uppermost of these contacts is spring biased to a closed position and is forced open when the padlock is inserted and `locked in position. The other two contacts of padlock AjPL are spring biased to an open position, but are normally forced closed by the padlock itself. In the normal condition shown in Fig. 1b, therefore, the uppermost contact 26 of padlock AP-L is shown as interrupting the circuit in which it is connected, while each of the two lower contactsV 57 and 63 are shown as completing the `circuit between the contact terminals.

The control or energizing circuit for switch lock AWL may then be traced from terminal B over front contact 25. of relay LR, contact 26 of padlock` APL, the winding of switch lock AWL, and front contact 2,7 of relay LR to terminal N. It is to be seen that, upon the removal of padlock APL by a trainman, the closing of Contact 26 completes` the circuit for energizing switch lock AWL, providing lock relay LR is energized to check that conditions are satisfactory for unlocking the hand throw lever of .switch WA. As previously indicated, the energization of switch lock AWL raises `armature 24 to lift the segment holding locking bar 23, thereby releasing hand throw lever HA for movement to its reverse position. It is to be noted that, upon the return of hand throw lever HA to its normal position, insertion of padlock APL in the switch lock mechanism will deenergize 'the lock magnet winding releasing armatureA 24 and thus locking the hand throw lever.

The hand throw lever HB associated with switch WB is provided with a similar electric lock arrangement. Lever HB is operatively connected to a locking bar 28 by a means shown conventionally lby dotted line 29. Locking bar 23 is retained in its right-hand position holding lever HB normal by the segment on armature 30 of electric switch lock BWL. Switch lock BWL is energized, to release the locking bar, by a circuit including front contacts 25 and 27 of relay LR and a normally open contact 31 controlled by padlock BPL.

Each switch has also associated therewith` a set ofcontact members which are connectedV to the switch points and/ or to the switch operating mechanism. These contact members are actuated between normal and reverse positions according to the operation of the switch points between their normal and reverse positions, respectively.,

The lower contact associated with each contact member is the normal contact, that is, the` contact member completes a circuit with the lower contact when the correspending switch is in its normal position. In a similar manner, the upper contact associatedwith each contact member is the reversecontact and the circuit is completed In the present case,

between the contact member and this upper contact when the corresponding switch is in its reverse position. 'The contact members and their associated normal and reverse contacts for switch WA are designated by reference characters 32 to 35, inclusive, while the contact members and contacts for switch WB are assigned reference characters 36 t'o 39, inclusive. Both sets of switch point contacts are shown identically in the drawings for simplicity.

Our invention also adds to the traine control apparatus a reverse switch repeater relay and a normal selector lever repeater relay for each switch. For example, associated with switch WA is the reverse `switch repeater relay ARWP. This relay is energized when an obvious circuit to terminals B and N of the source is completed over contact members 34 and 35, and their corresponding reverse contacts, associated with switch WA. Similarly, a reverse switch repeater relay BRWP associated with switch WB is energized when its circuit is completed over contact members and reverse contacts 38 and 39. It is to be noted that each of these repeater relays, when the corresponding switch is in its normal position, has its winding shunted over the corresponding normal contacts, so that the release of these relays is assured under switch normal conditions.

The normal selector repeater relay ANJP associated with switch WA is energized over a simple circuit completed by contact member 7 in its normal or power operation position. This contact member 7 was previously defined as being operatively connected with selector lever SA. It is thus to be seen that relay ANJP is energized only when lever SA occupies its normal or power operation position. A similar relay BNJP associated with switch WB is energized over contact member in its normal position when dual selector lever SB occupies its power operation position. Each of these normal selector repeater relays is deenergized when the corresponding lever is moved to the manual or hand operation position.

In addition, a reverse switch storage relay is provided for each ot the switches of the crossover. Each of these relays stores the reverse switch position indication while that switch is in manual control, that is, while the dual selector lever associated with the switch occupies its manual or handl operation position. For example, reverse switch storage relay ARWS associated with switch WA is energized over a `circuit including terminal B, back contact 40 of relay ANI P, front contact 41 of relay ARWP, the winding of relay ARWS, and terminal N. When relay ARWS picks up, it closes its front contact 42 to complete a stick circuit which also includes back contact 40 of relay ANH. It is to be seen therefore that even though switch WA, as controlled by hand throw lever HA, may be returned to its normal position, relay ARWS, when once energized, will remain energized through its stick circuit as long as dual selector lever SA remains in its manual operation position. Reverse switch storage relay BRWS associated with switch WB is energized by a circuit which includes back Contact 43 of relay BN] P, front contact 44 of relay BRWP, and the winding of relay BRWS. The stick circuit for this relay includes back contact 43 and front contact 45 of relay BRWS. The utility ofthe two RWS relays will be demonstrated hereinafter during the description of the operation of the traffic control apparatus of our invention.

As is usual in such remote control installations, each detector track relay has associated therewith a track indication storage relay, here the relays ITKS and 3TKS associated respectively with relays lTR and STR. With the track section unoccupied, the associated T-KS relay is held energized by a stick circuit. In the present arrangement, for example, with section 1T unoccupied by a train and other conditions normal, relay lTKS is held energized by a circuit extending from terminal B at front contact 46 of relay ITKS over front Contact 47 of relay ANIP, front contact 48 of relay BNI-P, front contact 49 of relay tTR, and the winding of relay lTKS to terminal N; lt is to be noted that this stick circuit, as well as the energizing circuit for relay ITKS and thev similar circuits for relay 3TKS, as will appear shortly, checks each dual selector lever in its normal position, that is, that the repeater relays of these levers are energized.

Since the TKS relays enter into the signal control circuits shown near the bottom of Fig. lb, this check of the dual selector levers ordinarily prevents the clearing of signals if either lever is out of its normal position.

A circuit extending over back contact 46 of relay lTKS to the remote control apparatus provides a track occupied indication to the remote oiiice location where the operator is stationed. Another circuit extending from this remote control apparatus provides pickup energy for relay llTKS, this circuit by-passing front contact 46 of relay lTKS, but including contacts 47, 48, and 49 previously described in the stick circuit for the relay. The full operation of this circuit arrangement is described in the previously mentioned iackel Patent 2,411,375. Briey, when the remote control apparatus is at rest, the stick circuit is complete and relay lTKS is held energized. lf track section 1T becomes occupied, so that relay lTR releases, the stick circuit is interupted and relay ITKS also releases. Relay 1'1`KS remains released, even though relay lTR again picks up, until its energizing circuit is completed in the coding unit during the transmission of an indication code. The main purpose of the connection from the remote control apparatus is thus to assure that the track indication is stored until such time as it maybe transmitted to the remote office location.

Relay 3TKS is provided with similar energizing and stick circuits, the stick 'circuit including fro-nt contact 50 of relay 3TKS, front contact 51 of relay BNIP, front contact 52 of relay AN] P, front contact 53 of relay STR, and the winding of relay 3TKS. 'Ilhe energizing circuit for this relay from the remote controlA apparatus bypasses front contact 50, but includes the remainder of the stick circuit just described.

The apparatus shown in the drawings also includes switch correspondence relays, that is, a normal switch corespondence relay ABNWC and a reverse switch correspondence relay ABRWC. Each of these relays checks the correspondence of the actual positions of both switches with the positions of switch control relays AW and BW and switch stick relay WS controlled vby the remote control apparatus. In the present arangement, the normal switch correspondence relay also checks the condition of both electric switch locks While the reverse correspondence relay checks the dual selector levers normal. The energizing circuit for relay ABNWC may be traced from terminal B at normal contact 54 of relay BW (Fig. la) over contact member and normal contact 36 associated with switch WB, nonmal contact 55 of relay AW, contact member and normal contact 32 associated with switch WA, wire 84, .back contact 56 of switch lock AWL, contact 57 of padlock APL, back contact 5S of switch lock BWL, contact 59 of padlock BPL, normal contact 60 of relay WS, the winding of relay ABNWC, contact 61 of padlock BPL, back contact 62 of relay BWL, contact 63 of padlock APL, back contact 64 of switch lock AWL, wire 85, contact member and normal contact 33, and Contact member and normal contact 37 to terminal N. It is to be noted that if any of the relays WS, AW, or BW has operated to its reverse position, the winding of relay ABNWC is shunted by reverse contact 54, 55, or 60 of these relays, so that this switch correl 'spondence relay releases quickly under these conditions.

The energizing circuit for reverse switch correspondence relay ABRWC includes front contact 65 of relay ANJP, front contact 66 of relay ARWP, front contact 67 of relay BNIP, front contact 63 of relay BRWP, reverse contacts 69 and 70 of relays BW and AW, respectively, wire 86, reverse contact 7l of relay WS, and the winding of relay ABRWC. It is to beV noted that both switches must be in their reverse position, as indicated by the reverse' switclnrepeaterl relaysl both selector levers .in their normal ortpowertoperation position, and a reverseswitch called fortby. relays.-\l\lS,` AW, and BW before the reverse switclr.correspondence-relay can `be energized. Under Ithefnormal conditions shown, the. windingV of relay ABRWCgZis `shunted .by :normal contact 7l ofrelay WS. Other shuntcircuits maybe established over normal contacts69f.and 70.0frelays BW andAW if appropriate.

4The on-ly remaining relays not already discussed here-` tofore-.areuthe approachlock or stick relays AS, there beings one .such relayfor each signal. For example, relay ZRSfis-associatedwith ysignal 2R; No `control circuits are..shown-for these `four relays since suchcircuits are notpartoftiour invention, butthey `may be controlled throught-.the signal'stick relays of `the remote control apparatus ina .manner .shown in Letters Patent of the United y States 2,567,834, granted September ll, 1951, to .Earl1M.' Allenfor .a` Centralized Tratic Control System for Railroads Aforltlie Code Control ofInterlockedTrack SwitchesandSignals. Such controls are well `known and it believed unnecessary to repeat them here. It is suicient.to-statethat.each ot` these relays releases if the corresponding signallisto `be cleared, that is, a signal-clear control .hasbeentransmitted from Vthe. control oce, and remainsA released while the associated signalremains in the clearvconditionor. in .a time lock condition. Such control 'ottthesignalicontrol circuits. as is exercised by the approach lock. relays AS will -be described during the following operationali description. of the apparatus.

lWefshall now describe thev operation of the apparatus as itrfunctions under a specific situationoif` switching moves. on onemain.track, while a through train moves over thev second lmain track.

As shown `in the drawings, the condition of the apparatusand `track is normal, that is, there are no trainsin the interlocking, both switchesV are in their normal position and in power operation, hand throw levers arev locked in the'proper-.positionby the electric locks with padlocks in place, all Lsignals are at stop, and the remote control apparatusisat rest. Under these conditions, relays TR, TICS,A NJP, AS', LR, and NWC are all energized. Correspondingly, relays RWP, RWC, RWS,` and WL are deene'rgized.4` Relay WSrernains in the position towhich it Waslast operated, that is, its normal position with normal contacts closed. Relays AW and BW are energized with current-of -normal polarity, so that their front neutralcontacts and normal polar contacts are closed.- Switch movements SMA and SMB are deenergized, having completed the` full movementof the switch` points to their normal position in accordance with the last control from theswitch control relays.

Wevshall now-assume that a local train crew. requests permissionto use theupper track for switching moves. InJ otherwords, the crew desires to move their train back andforth throughv track section `1LT without regard to the signal-indications, Yas several such moves in a short time arerequiredltoperformthe desired work. lf such operation is to-fbe allowed, Interstate Commerce Commission safety rules requirethat switch WA be placed in manual orhandloperation, in order to prevent the remote control operatorfrom inadvertently controlling the switch to its reverse position. Under such conditions, the remote operator may also block the No. 2 signal lever on his machinmsothathe will `be remindedas to the local conditions.V Itis-further assumedthat the operator will shortlydesireto clear signal 4L to authorize a through train movementonthe lower track, that is, through section 3T overlswitchfWBinits normalposition. He therefore grantsthe request of the local` train crew, but instructs thenitoremainnclear of the lower main track, using the uppertrackl onlyf In other-words, the hand throw lever for switch- WA must be electrically locked in its normal position, `in` addition to placing the switch in manual operation.` I-lowevenr` for absolute safety, switch WA rrilitibeln'iovedrb-yfhandA throw'lever HA to its reverse position then-,returnemtqthenormal position and then.

electrically locked. This assuresthat ,the hand throw leverhasbeen gearedto `the switch throw rodafter the ydual selector lever is moved from its power toymanual` cannot then become misaligned fromtheir. normal position. If such misalignment occurred, the local train might,

inadvertently-foul the other main track without sufficient vor timely protection against approaching trains.

erally be specifiedin therrailroads operating rules.

Having` received this permission to make such switching or drilling moves, a trainmanfrom the local train Vunlocks dual selectorlever SA, which is generally heldV in place by an ordinary switch padlock as` protection against` unauthorized personnel, and moves the lever to the manual operation position. This causes Vlink J A to move from its normal or right-hand position to the left-hand position, interrupting .the control of switch WA by switch movement SMA and placing that switch under the control ofhand throw lever HA. In addition, contact member 7 is moved` to its left-hand position interrupting the circuitfor relay A-NIAP, which immediately releases. The

release of relay ANJP to open its front,contacts 47 andV 52 deenergizes relays ITKS and STKS, respectively. These latter relays release shortly and, as a result of the closing of `their backy contacts 4,6 and 50, cause track occupied indications` to be transmitted to the remote oilice where the indications are recorded. in the usual manner inthe control machine. and 3` 'IKSalso interrupts. the signal control circuits to assure thatthe clearing "ofl any signal at the present time isvprevented. Reception and display of the track occupied indications atV the .remote control otce indicates to the. operator `that conditions lare not normal at this crossover location.

The trainrnan nowgunlocks and `removes padlock APL, causing contact 26 to close and contacts 57 and 63 to open, Vas was previously described. The closing of contact 26 completes the energizing circuit for electric switch lock AWL, provided that lock relay LR- is energized at this time. Aswaspreviously explained, relay LR is re- -leased if either track section 1T or 3T is occupied or if any one of the signal approach locks relays AS is released, denoting` that =a signal is to be cleared or has been cleared. Thus the contacts of this relay in the circuit for switch locks AWL and BWL provide a check that all conditions, areproper for the unlocking of the handl throwtlever of either switch. Assuming atl present that relay LR- is energized, since conditions were originally statcdas beingv normal, switch lock AWL is now energized.

When padlock contactsg57- and 63 open, relay ABNWC is deenergized and releases. The circuit for this latter relay is further. interruptedl at a second point by the opening of back contacts 5.6 .and 64of switch lock AWL. Release of relay ABNWC further interrupts the signal controlcircuits, as4 will be described shortly. The picking up of armature Z4-of switch lock AWL releases locking bar ZSand-allows hand throw lever HA to be moved as desired. At this time, the trainman may operate lever HA toits reverse position, thus reversing switch WA,

, closing its switch pointsin the reverse position.

When switch WA` is` reversed, the associated contact membersiare correspondingly moved and the closing of reverse contacts 34 and `3.5 energizes relay ARWP, as previously explained. The closing `of front contacts of `this latter relay-completes the circuit for energizing the reverse switch Istorage relay ARWS, this circuit including back contact 40 of relay ANI P and front contact 41 of relay ARWP.` `Relay ARWS, thus energized, picks up and completes a stick `circuit at front contact 42, this circuit also including back contact 40'. Itshouldbe noted This predetermined sequence of manual operations will gen-V Release of relays ITKS4 114 at this time that even though one switch is in its reverse position, relay ABRWC is not energized, since the reverse switch is not called for by any of the switch control relays.

The trainman now operates lever HA to return switch WA to its normal position. This interrupts the circuit for relay ARWP which immediately releases, this release being aided by the shunt placed upon the relay winding by contact members and normal contacts 34 and 35. However, relay ARWS holds in its energized condition, the stick circuit previously described remaining effective while lever SA remains in its manual operation position. As soon as switch WA is returned to its normal position', padlock APL is returned to its usual position in the mechanism and is locked. The opening of padlock contact 26 deenergizes switch lock AWL which immediately releases. Hand throw lever HA is thus locked in its normal position by the release of armature 24 which blocks the movement of locking bar 23. Release of switch lock AWL `also completes again the energizing circuit for relay ABNWC by the closing of back contacts 56 and 64, the contacts 57 and 63 associated with padlock APL having previously been closed. It may be noted that during this entire operation relays WS, AW, and BW have remained in their normal position since no switch control has been transmitted from the remote oice location.

When relay ARWS picks up, a circuit is completed for energizing relay BTKS, as soon as the remote control apparatus completes any coding action resulting from the release of the two track indication storage relays. As soon as the remote control apparatus is at rest, energy is supplied from terminal B to the circuit by-passing contact 50 of relay STKS and extending over front contact 51 of relay BN] P, front contact 72 of relay ARWS, front contact 53 of relay STR, and the winding of relay STKS to terminal N. It is to be remembered that, under the assumed conditions, relay STR is energized since track section 3T is unoccupied. Relay BNI P is also energized since 4dual selector lever SB associated with switch SWB has not been moved from its power operation position. The energization and pick up of relay STKS when the remote control apparatus is `at rest is fully explained in the previously mentioned Iackel patent and reference is made to this publication for additional details of the action. However, relay 1TKS remains deenergized at this time since its energizing circuit is interrupted at front contact 47 of relay ANI P. A second point of interruption of this circuit will also occur yat front contact `49 of relay liTR when the local train occupies section 1T.

The trainman having completed the necessary actions, the local train is free to movev or drill back and forth over switch WA and section 1T as often as desired. At thesame time, the remote control operator vis free to clear signal 4L when he so desires by transmitting the usual control from the oce to the local remote control apparatus for this purpose. Upon receipt of this signal control, relay 4LAS is deenergized and releases. This completes a circuit for clearing signal 4L, which may be traced from terminal B over front contact 73 of relay lZ-RAS, front contact 74 of relay ABNWC, back contact 75 of relay LR, which hasreleasedgat this time, front contact 7 6 of relay STKS, back contact 77 of relay 4LAS, and thence through circuits not here shown including the mechanism of signal 4L to terminal N. These remaining circuit details for the clearing of Vsignal 4L are not here shown as they are not part of our'invention and are well known in the art. The actualy indication disprevent the energization of switch' lock AWL so that` switch WAY is retained locked in its normal position. f.

It 'is obvious that signal 4R could also be cleared if desired in place of signal 4L, the portion of the circuit shown being obvious from an inspectionv of the drawings. The clearing of either of these signals as desired may be accomplished with complete safety under the existing conditions. The operation of switch WA by handk throw lever HA to its reverse position and then back toas long as relay ANJP is released. The circuits for the.

control of switch WB may even be arranged, if desired,

so as to prevent the switch from being operated at all under these conditions. The operator thus retains control of the one through or main track route'while ther other switch is in manual or hand throw operation.

It is obvious that the situation as assumed may be reversed. and receive permission to place switch WB in hand throw operation and drill the local train back and forth across.

section 3T. If the actions are completed inthe proper sequence, the remote operator retains control of signals 2L or 2R under these conditions so that through movements on the upper main track may be authorized. Under these conditions, relay BRWS is energized when switch.

WB is thrown to its reverse position under manual control and remains energized as long as relay BNJP remains released. Relay lTKS will then be reenergized by the closing of front contact 78 of relay BRWS to bypass the open front contact 48 of relay BNJP in thecir-` cuit for relay lTKS in the same manner as explained for relay STKS. Electric switch lock BWL is energized by the removal of padlock BPL from its usual position to i close contact 31. After the switch WB is operated reverse and then normal and the padlock replaced so that-switch lock BWL releases, relay ABNWC will again be energized through its previously traced circuit. Either signal 2R or 2L can then be cleared, the circuits including vin part front or back contacts 79 and 80 of relays ZRAS and ZLAS according to the signal to be cleared, front contact 81 of relay ABNWC, back contact 82 of relay LR, and front contact 83 of relay ITKS.

From the preceding `discussion it is obvious that by the simple arrangement provided by our invention, the traffic control apparatus shown permits the use of vone of the main tracks at the crossover interlocking by a local train for switching purposes with the corresponding switch in manual operation, while-the remote operator retains control of the through route along the other main track over the other switch of the crossover.

ratus so that both movements may be made with complete safety. Results are yobtained with a minimum of `additional apparatus over that required' to remotely control the interlocking in the usual manner, that is, without the special feature.

Although we have herein shown anddescribed but one form of traflic control apparatus embodying our in-j vention, it is to be understoodthat Various changes andv modifications may be made therein within the scope` of the appended claims without departingfromthe spirit and scope of our invention.

Having thus described our invention, what we claim is:v

1. In a railway signal system for governing train movements through an interlocking comprising a crossover between two m-ain tracks having a switch at each end -of the crossover which occupies a reverse position to divert trains to said crossover and a normal position .flor through.,

In other words, a switch crew may request 13 train movements along the corresponding main track, said system including a power switch movement for each switch to operate the associated switch between its two positions, la hand throw lever fora rst of said switchesto operate that switch between its two positions, a selector lever to selectively connect the corresponding `power movement and said hand throw lever to operate said first switch, and signals to control train movements in each direction over the second switch along the corresponding main track; the combination comprising, a storage means operably connected to said selector lever and to said irst switch for recording an indication f the movement of said first switch to its reverse position by said hand throw lever and for retaining that indication as long as said selector lever is positioned to connect said hand throw lever to said tirst switch, a switch correspondence means controlled by both switches for detecting when both switches occupy their normal positions, and a signal control means controlled by said storage means and by said correspondence means for clearing a selected one of said signals when both switches occupy their normal positions and said storage means is retaining an indication of a manual operation of said first switch to its reverse position.

2. In a railway signal system for governing train movements through an interlocking `comprising a crossover track between two main tracks, said crossover track being joined at each end to a main track by a track switch which occupies a reverse position to divert trains to said crossover track and a normal position for through train movements on the corresponding main track, said system including a power switch movement and a manual lever for each switch `to operate the associated' switch between its normal and reverse positions, a selector lever associated with each switch for selectively connecting the corresponding manual lever and the correspondingwpower movement to operate said switch, and signals to control the entrance of a train into said interlocking from each direction along each main track; the combination comprising, repeater means for detecting when the selector lever for a iirst of said switches selectively connects the corresponding power movement andthe corresponding manual lever to operate that switch, a storage means controlled by said repeater means and operably connected to said iirst switch for recording an indication that said first switch has been manually moved to its reverse position and for storing that indication aftersaid first switch is returned tfo its normal position as long as said repeater means indicates that said iirst switch selector lever continues to occupy its manual lever selecting position, a switch repeater means operably connected to both switches for indicating when both switches occupy their normal positions, and a signal control means controlled by said switch repeater means in its switch `normal condition and said storage means in its reverse indication condition for clearing a selected one of said signals to authorize a through train movement over the second switch when'said first switch selector lever connects the manual lever to operate said iirst switch.

3. At a railway interlocking including a crossover connected by a iirst and a second` track switch -to a iirst and a second main track respectively, each track switch occupying a normal position for through train moves and a reverse position to divert trains to said crossover, a power switch movement and a manual lever for each switch to operate the associated switch between its normal and reverse positions, a selector lever associated with each switch for selectively connecting the corresponding power movement and the corresponding manual lever to operate said switch, an electric switch lock associated with each switch for locking the corresponding manual lever in the switch-normal position, a plurality of signals for controlling train movements through said interlocking, a selector repeater means controlled by the selector lever associated with said first switch for 1'4 detecting `when said vlirst switch selector lever connects the corresponding power movement and the corresponding manual lever to operate said iirst switch, reverse switch storage means controlled by said selector repeater means `and by said iirst switch for registeringanindication tof the manual operation of said iirst switch to -i-ts reverse position and for retaining the :reverse switch indication while said iirst switch selector lever occupies its .manual lever selecting position, a track occupancy storage means for a section of said second maintrack including said second switch and also controlled by said selector repeater means for indicating a normal trackunoccupied condition when said second track section'is unoccupied and said rst switch selector lever .is` in-'its power movement selecting position, the. controlof `said occupancy storage means by said selector repeater .means being bypassed by said switch` storage means when-la reverse switch indication is stored 'for restoring said occupancy storage means `toits normal indication, switch lock releasing means for unlocking said switch locks, switch correspondence means controlled byboth switches and by both switch locks for indicating a correspondence condition when both switches occupy normal Y.positions and both manual levers are locked in the switch-normal position, and `signal control means controlledtby said occupancy storage means `and said correspondence-means when a normal and a correspondence condition respectively are indicated for clearing a selected signal `to` authorize a through train movement over said second main track whensaid iirst switch selector lever occupies movement for each switch provided with :a dual selector` lever operable to a first position to select operation of the associated switch by said power movement and to a second position to select manual operation of said associated switch, a reverse switch storage relay for each switch energized over a switch repeater contactfclosed when the corresponding switch occupies its reverse position and al'ever repeater contact `closed only if the associated selector Vlever occupies its second position, a stick circuit for each said reverse switch storage `relay including a front contact of that relay and s-aid lever repeater contact closed while said associated selector lever continues to occupy its second position, a track occupancy storage rrelay for the track section.` of saidjone main track including the corresponding switch, van` energizing circuittor said track storage relay including ,a track repeater contact normally closed when `said track section is unoccupied by a train, anotherl repeater Vcontact for each selector lever closed when the associated` selector lever occupies its first position, 'and a front contact of the reverse switch storage relay associated with the switch in said other main track connected in multiple with the corresponding other selector lever repeater contact; a signal governing main track moves through said track section and a control circuit therefor to energize said signal to its proceed indication, said control circuit including a signal selection contact controlled by said traiiic control system, a correspondence contact closed only when both switches are locked in the normal position, and a front contact of said track occupancy storage relay; whereby said signal is energized to its proceed indication when the selector lever associated withl the other track switch occupies its second position.

5. YIn a traiccontrol system for railroads, at a crossover track between two main tracks connected to each main track by a track switch, each switch being operable between a normal position for a main track train movement and a reverse position to divert a train to said crossover track, a signal control arrangement to authorize a main track train movement over one of said switches with the other switch in manual operation only after the completion of a predetermined sequence of manual operations of said other switch, comprising in combination, a power switch movement for each switch provided with a dual selector lever operable to a first position to select operation of the associated switch by said power movement and to a second position to select manual operation of said associated switch, a repeater relay for each selector lever energized only when the associated selector lever occupies its first position, a reverse switch repeater relay for each switch energized only when the associated switch occupies its reverse position, a reverse switch storage relay for each switch and an energizing and a stick circuit therefor, said energizing circuit including a back contact of the corresponding selector lever repeater relay and a front contact of the corresponding reverse switch repeater relay, said stick circuit including afront contact of the switch storage relay itself and said selector lever repeater relay back contact; a signal govern-- ing main track train movements over said one switch, a track occupancy storage relay for the track section including said one switch and an energizing circuit therefor including in multiple front contacts of the selector lever repeater relay and the reverse switch storage relay associated with said `other switch, and a control .circuit to. energize said signal to display a proceed indication, said control circuit including a signal selecting contact controlled by said tratlic control system, a correspondence contact closed only when both switches are locked in their normal position, and a front contact of said track occupancy storage relay, whereby said signal may display a proceedtindication with the 'selector lever associated with said other switch occupying its second position.

6. At a railway interlocking including a crossover between two main tracks connected by a track switch at each end to the corresponding main track, each switch being operable between a normal position for a main track train movement and a reverse position to divert a train movement over said crossover, each switch being provided with a power switch movement, a hand throw lever, and a dual selector lever to select between said movement and said hand throw lever for switch operation according as said selector occupies a lirst or a second position respectively; a circuit arrangement to enforce a predetermined sequence of manual switch operations of a lirst switch comprising a reverse switch storage relay for said first switch having an energizing circuit including a repeater contact closed only when the associated selector lever for said tirst switch occupies its second position and a switch repeating contact closed only when said first switch occupies its reverse position, a stick circuit for said switch storage relay including its own front contact and said associated selector lever repeater contact, a track occupancy storage relay having an energizing circuit including a track repeater contact closed when the main track section including the second switch is unoccupied by a train, a repeater contact closed when the selector lever associated with said second switch occupies its first position, and in multiple a front contact of said switch storage relay and another repeater contact closed when said first switch selector lever occupies its first position, whereby said track storage relay is energized if the first switch is manually operated to its reverse position and returned to its normal position after said iirst switch selector lever is moved to its second position; and a control circuit including a front contact of said track storage rela 7.y'At a railway interlocking including a crossover between two main tracks connected by a track switch at each end to the lcorresponding main track, each switch being operable between av normal position for a main track train movement and .a reverse position to direct a train movement over said crossover, each switch being provided with a power switch movement, a hand throw lever with an electric lock therefor, and a dual selector lever operable to a tirst and a second position vto select between said movement and said hand throw lever respectively for switch operation; a circuit arrangement to enforce a predetermined sequence of manual switch operations of a first switch prior to electrically locking the associated hand throw lever in the switch normal position including a reverse switch repeater relay energized only when said first switch occupies its reverse position, a selector lever repeater relay energized only when the selector lever associated with said first switch occupies its first position, a reverse switch storage relay energized over a front contact of said switch repeater relay and a back contact of said selector lever repeater relay, said switch storage relayhaving a stick circuit including its own front contact and said selector lever repeater relay back contact; a track occupancy storage relay having an energizing circuit including a track repeater contact closed when themain track section including the second switch is unoccupied by a train, a repeater contact closed when the selector lever associated with said second switch occupies its first position, and in multiple front contacts of said selector repeater relay and said switch storage relay, whereby said track storage relay is energized if the irst f switch is manually operated to its reverse position and returned to its normal position after the first switch selector lever is moved to its second position; and a control circuit including a front contact of said track storage relay and a correspondence contact closed only if both switches occupy their normal positions and each hand throw lever is electrically locked in the switch normal position by the corresponding electric lock.

References Cited in the file of this patent UNITED STATES PATENTS 2,025,574 Dalzell Dec. 24, 1935 2,060,488 Van Horn Nov. l0, 1936 2,539,937 Thompson Ian. 30, 1951 2,567,050 Broadbent Sept. 4, 1951 2,774,863 Johanek Dec. 18, 1956 

